"She amd Isshiki werent the ones who necessarily planted the tree or they may have done the planting/sacrificing earlier and come back later, this time being the one that was recorded"
That's not what Amado said. He was quiet clear: Otsutsukis invade planet in pair, one implants karma in new vessel and is sacrificed to 10 tails, the other is watching over Divine Tree and waiting for Chakra Fruit to appear. It is possible Kaguya used Karma and sacrificed herself, but that would make the whole betrayal part stupid.
True that Kishimoto rushed the whole Kaguya part in manga and now writers try desperately to fill blanks and come up with something, but to be honest, I feel like they've made mistake by using Otsutsukis in the first place. Should have just drop them after Momoshiki and Kinshiki and came up with something else.